The present invention relates to a pin-board matrix switch used for a main distribution frame or the like for a communication network in house wiring or the like.
With the recent advances in intelligent buildings, various electric wires are jumbled in the buildings. Of these wires, wires constituting house wiring installed on a floor are classified into wires for a telephone system and wires for a LAN system. In many cases, coaxial cables have been used for the wires for a LAN system. There is a tendency to install twisted pairs of wires so as to facilitate a wiring work or facilitate management of wiring by unifying wires for a telephone system and a LAN system. Congestion of floor wiring, i.e., disorderly installation of various kinds of cables, is one of the problems posed in a recent intelligent building. In order to solve this problem, a preliminary wiring work is performed by using twisted pairs of wires for floor wiring use under predetermined wiring management. Afterward, actual wiring work is performed in a patch panel on demand.
This patch panel wiring, however, is performed manually. Although systems for automatically performing wiring management have already been developed and commercially available, a patch panel itself is manually installed. For this reason, an actual work result may disagree with wiring management data. In addition, cumbersome wiring operations must be manually performed in a patch panel wiring work, and it is difficult to change wiring.
Under the circumstances, a pin-board matrix switch is used. With this switch, wiring can be easily changed by inserting/removing a connecting pin, and an automatic wiring work can be easily realized. This pin-board matrix switch can be manufactured by general printed board techniques and hence can be realized at a low cost. At the same time, a high-density switch can be realized. Therefore, the pin-board matrix switch is suitable for a reduction in size.
On the other hand, a conventional pin-board matrix switch is only capable of allowing from telephone lines and up to 320-kbps time compression multiplexing transmission lines for ISDN basic interface (i.e., only capable of providing services via metal wires), but cannot keep up with the speed of a high-speed LAN demanded in the future.
A conventional pin-board matrix switch like the one shown in FIG. 32 is disclosed in Japanese Patent Laid-Open No. 1-276524. This switch will be described below with reference to FIG. 32. A pin-board matrix switch denoted by reference numeral 5 as a whole is constituted by a matrix board 9 and a connecting pin 51. The matrix board 9 is formed by alternately stacking insulating substrates 11, 12, 13, and 14, each having an electroless plating catalyst dispersed therein, and insulating substrates 16, 17, and 18, each containing no electroless plating catalyst. Reference numerals 21 and 22 denote Y-direction patterns formed on the first layer; 211 and 221, Y-direction patterns formed on the third layer; 31, an X-direction pattern formed on the second layer; and 311, an X-direction pattern formed on the fourth layer. A signal line is constituted by the Y-direction patterns 21 and 211 and the X-direction patterns 31 and 311, which oppose each other in the Z direction.
Reference numeral 41 denotes a crosspoint hole formed at the crosspoint between X- and Y-direction patterns and incorporating a contact 42 electrically connected to the Y-direction pattern 21 on the first layer and a contact 43 electrically connected to the X-direction pattern 31 on the second layer; and 51, a connecting pin having a pair of contact springs 53 and 54 arranged on an insulating shaft 52. When the connecting pin 51 is inserted into the crosspoint hole 41, contacts 42 and 43 and contacts 44 and 45 (not shown) are electrically connected to each other via the contact springs 53 and 54. As a result, the Y-direction pattern 21 on the first layer and the X-direction pattern 31 on the second layer are electrically connected to each other, so are the Y-direction pattern 211 on the third layer and the X-direction pattern 311 on the fourth layer.
In the above conventional pin-board matrix switch, since a plurality of patterns are arranged at small intervals, large crosstalk is induced from an adjacent pattern pair. For this reason, a high-speed signal line cannot be accommodated.
In the conventional pin-board matrix switch 5, when, the connecting pin 51 is inserted into the crosspoint hole 41 to set a route having a short signal transmission distance, a pattern (to be referred to as an open line) extending from the crosspoint hole 41 to a crosspoint hole 42 in an end portion of the matrix board is added, in an open state, to the signal transmission route. For this reason, as the signal speed increases, and the wavelength of a signal approaches the size of the matrix board 9, variations in characteristic impedance due to a stray capacitance become conspicuous, resulting in a considerable deterioration in the transmission characteristics of the pin-board matrix switch 5. Furthermore, as the signal speed increases, crosstalk in an open line cannot be neglected, resulting in a deterioration in the transmission characteristics of the pin-board matrix switch. For this reason, the conventional pin-board matrix switch 5 cannot accommodate a high-speed signal line.